1. Field of the Invention
The invention relates to a release element for a thermal and/or electrical release of a fire-protection system, in particular a sprinkler system, where the release element formed from glass is filled up to bursting with a liquid.
2. Brief Description of the Background of the Invention Including Prior Art
Such release elements keep the valves in sprinkler heads closed and are to be destroyed by expansion of the bursting liquid in case of a fire. The release elements have to perform two functions. On the one hand, they have to receive the tensioning forces in order to keep the valve constantly in a closed state if there is no fire and, on the other hand, they have to burst quickly in case of a fire, such that the extinguishing process is initiated quickly. In addition, the sprinkler heads have to remain in a functioning state over decades.
In order to combine the two functions in an optimum manner, a number of release elements are known. For example, the increase of the tensioning forces by a different forming of the glass release elements has been attempted to be achieved in the U.S. Pat. No. 1,733,701 without extending the bursting time. It is further known to decrease the bursting time by inserting a displacement body inside of the bursting liquid (German Patent Application Laid Open DE-OS 3,220,124).